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1 Fishing Agriculture which is also known as fish farming is a commercial activity. In this activity, fish are raised in tanks and other enclosures. Fish hatchery technique is used for raising immature fish into mature fish in a natural way. The most common species of fish which are raised for fish farming are carp, cod, catfish and salmon. This business is expanding with a wide pace to meet the increasing demand. Fish are in demand for different cuisines and fish protein. Fish agriculture is of two types - intensive agriculture and extensive agriculture.

2 A massive production can be done through this technique as it needs oxygen, food and fresh water. A massive water filtration system is also needed to purify the fresh water so that there may be no risk of algae or other bacteria in the tank. A combination of water treatment and hydroponic system is the best way to keep the fresh water clean and bacteria free. The expenditure of this kind of fish farming is higher to the extensive fish farming because of high protein fish food. This kind of fish farming has a risk of infection from parasites such as fungi, intestinal worms, bacteria, fish lice and protozoa. This type of fish agriculture needs adequate quantity of oxygen, nitrite and oxygen to minimize the risk of encountering with any problems. This type of agriculture needs high level of expertise.

3 In this technique, the fish are kept and fed in natural ways. They are provided the natural environment to grow. These fish are offered appropriate temperature, sunlight and food supply which help in optimum growth. With these facilities, the fish expand their growth. Although, this is a natural and safe way of fish farming but there is a high risk of algal bloom. This occurs when algae grow and multiply their biomass at an intensive rate. This exhausts the nutrients and oxygen in the water and releases organic and inorganic solutes like ammonium ions which lead to substantial fish loss. To prevent this situation, the aqua culturists suggest various pond ecosystems such as filter algae feeder, benthic feeder and weed feeders. This is a very limited of farming fish in natural or semi-natural ponds.

4 Another good way of fish agriculture is composite fish culture system. Four or five species of fish is raised in a single pond so that they may not compete with each other for necessities as they belong to different habitats. This way they all grow in a healthy way. Calta, silver carp, mrigal, rohu and common carp are some of the species of fish which are appropriate for this kind of fish agriculture system. Special monitoring equipments are used to keep a track over these fish so that they may grow in a better way.

5 Fish farming is currently one of the world's fastest growing food industries. Denmark has a long tradition of fish farming and today is among the world leaders in equipment for green production, thanks to the development of so-called model fish farms. The high-tech and environmentally friendly model fish farms use water from boreholes, rather than from rivers, and are based on water recirculation technology. This means that the fish farm recycles as much as 95 percent of the water instead of merely letting it drain away into the countryside.

6 Now DTU Aqua and several of the key players in the industry are joining forces to take Danish fish farming a stage further. In order to put large rainbow trout and salmon on the menu as well, the so-called model fish farms are to be expanded to include the breeding of saltwater fish as well as freshwater fish -- and it is to take place inland. The project is being supported by the Ministry of Food, Agriculture and Fisheries' Green Development and Demonstration Programme (GUDP).

7 "The global salmon market is huge. The production of fish in the aquaculture industry is increasing in several countries, but so far Denmark has not increased production significantly, mainly because of environmental restrictions,. But why should the Norwegians produce our salmon if we can do it just as well -- and without compromising the environment?" asks technical project manager Per Bovbjerg Pedersen, from DTU Aqua in Hirtshals.

8 More fish, less pollution In order to increase production in a sustainable and profitable manner, we need cross-disciplinary collaboration on new technological solutions for breeding fish in salt water to complement those solutions that DTU Aqua has already helped to develop within the field of freshwater fish breeding.

9 "The goal is to produce more fish, but with the same or even lower emissions of nitrogen out into the environment. This will be done partly through applying a known technique in freshwater farming, whereby bio-filters are used to convert the ammonia excreted by the fish into nitrate. Now the goal is to develop the technology to do the same with salt water, in order to convert this nitrate into nitrogen which can be released as a harmless gas. In this way the nitrogen is removed safely from the water," explains Per Bovbjerg Pedersen.